SaVi is satellite visualization software that lets you create, run, examine, and modify satellite orbits in two and three dimensions. Simulations of Iridium, Globalstar, Galileo, GPS, and other satellite constellations are included. SaVi requires Tcl and Tk on a system with Unix libraries. SaVi works well with the 3D renderer Geomview. Geomview is optional, though recommended for its 3D rendering capabilities.

libquantum is a C library for the simulation of
quantum mechanics, especially for quantum
computing. It provides an interface for a quantum
register and for all important quantum operations.
An efficient model for decoherence allows an
analysis of quantum computation in a realistic
environment.

Gwyddion is a modular SPM (Scanning Probe Microsope) data visualization and analysis tool. It can be used for all most frequently used data processing operations including: leveling, false color plotting, shading, filtering, denoising, data editing, integral transforms, grain analysis, profile extraction, fractal analysis, and many more. The program is primarily focused on SPM data analysis (e.g. data obtained from AFM, STM, NSOM, and similar microscopes). However, it can also be used for analyzing SEM (scaning electron microscopy) data or any other 2D data.

Geant4 is a toolkit for the simulation of the
passage of particles through matter. Its
application areas include high energy physics and
nuclear experiments, medical, accelerator, and
space physics studies.

The CWP/SU Seismic Un*x (SU) package is a software environment for seismic processing and seismic and wave-propagation related research. It is used not only in seismology but in other areas involving time-dependent data, such as Ground Penetrating RADAR.

Yet Another Dynamic Engine (YADE) is an extensible
framework that is designed with dynamic libraries
in a way that it is easy to add new numerical
models and objects. There are four different
models: Discrete Element Method based on spheres,
a second method based on tetrahedra, modelling
with lattice elements, and Finite Element Method.

CONSIDEO MODELER allows you to mindmap a complex
problem, analyse it qualitatively to discover
levers and bottlenecks, and even to simulate it by
automatically building a system dynamics model.
One can integrate any external data and setup a
customized management cockpit for playing out
scenarios. It is useful for organizational
problems, project management, financial analysis,
production processes, score cards, and much more.

octopus is a program aimed at the ab initio
virtual experimentation on a hopefully ever
increasing range of systems types. Electrons are
describe quantum-mechanically within the
Density-Functional Theory (DFT), in its
time-dependent form (TDDFT) when doing simulations
in time. Nuclei are described classically as point
particles. Electron-nucleus interaction is
described within the Pseudopotential approximation.